OFDMA with adaptive subcarrier-cluster configuration and selective loading
First Claim
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1. A method, comprising:
- transmitting, at a first time by a base station, at least a first pilot symbol to a subscriber unit for measuring the at least a first pilot symbol and obtaining first channel and interference information for a plurality of orthogonal frequency division multiple access (OFDMA) subcarriers;
receiving, by the base station from the subscriber unit, after the transmitting of the at least first pilot symbol to the subscriber unit, first feedback of channel and interference information relating to at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receiving of the first feedback of channel and interference information includes receiving a first indication of a modulation and coding rate associated with a first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a second indication of a modulation and coding rate associated with a second OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers;
transmitting, by the base station to the subscriber unit, a first allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receiving of the first feedback of channel and interference information;
transmitting, at a second time after the first time, by the base station, at least a second pilot symbol to the subscriber unit for measuring the at least second pilot symbol and obtaining second channel and interference information for the plurality of OFDMA subcarriers;
receiving, by the base station from the subscriber unit, after the transmitting of the at least second pilot symbol to the subscriber unit, second feedback of channel and interference information relating to the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receiving of the second feedback of channel and interference information includes receiving a third indication of a modulation and coding rate associated with the first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a fourth indication of a modulation and coding rate associated with the second OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers; and
transmitting, by the base station to the subscriber unit, a second allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receiving of the second feedback of channel and interference information.
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Abstract
A method and apparatus for allocating subcarriers in an orthogonal frequency division multiple access (OFDMA) system is described. In one embodiment, the method comprises allocating at least one diversity cluster of subcarriers to a first subscriber and allocating at least one coherence cluster to a second subscriber.
433 Citations
32 Claims
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1. A method, comprising:
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transmitting, at a first time by a base station, at least a first pilot symbol to a subscriber unit for measuring the at least a first pilot symbol and obtaining first channel and interference information for a plurality of orthogonal frequency division multiple access (OFDMA) subcarriers; receiving, by the base station from the subscriber unit, after the transmitting of the at least first pilot symbol to the subscriber unit, first feedback of channel and interference information relating to at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receiving of the first feedback of channel and interference information includes receiving a first indication of a modulation and coding rate associated with a first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a second indication of a modulation and coding rate associated with a second OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers; transmitting, by the base station to the subscriber unit, a first allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receiving of the first feedback of channel and interference information; transmitting, at a second time after the first time, by the base station, at least a second pilot symbol to the subscriber unit for measuring the at least second pilot symbol and obtaining second channel and interference information for the plurality of OFDMA subcarriers; receiving, by the base station from the subscriber unit, after the transmitting of the at least second pilot symbol to the subscriber unit, second feedback of channel and interference information relating to the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receiving of the second feedback of channel and interference information includes receiving a third indication of a modulation and coding rate associated with the first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a fourth indication of a modulation and coding rate associated with the second OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers; and transmitting, by the base station to the subscriber unit, a second allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receiving of the second feedback of channel and interference information. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A base station, comprising:
a transceiver configured to; transmit, at a first time, at least a first pilot symbol to a subscriber unit for measuring the at least a first pilot symbol and obtaining first channel and interference information for a plurality of orthogonal frequency division multiple access (OFDMA) subcarriers; receive, from the subscriber unit, after the transmitting of the at least first pilot symbol to the subscriber unit, first feedback of channel and interference information relating to at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receiving of the first feedback of channel and interference information includes receiving a first indication of a modulation and coding rate associated with a first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a second indication of a modulation and coding rate associated with a second OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers; transmit, to the subscriber unit, a first allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receipt of the first feedback of channel and interference information; transmit, at a second time after the first time, at least a second pilot symbol to the subscriber unit for measuring the at least second pilot symbol and obtaining second channel and interference information for the plurality of OFDMA subcarriers; receive, from the subscriber unit, after the transmission of the at least second pilot symbol to the subscriber unit, second feedback of channel and interference information relating to the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers, the receipt of the second feedback of channel and interference information includes receiving a third indication of a modulation and coding rate associated with the first OFDMA subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers and a fourth indication of a modulation and coding rate associated with the second subcarrier of the at least one subset of OFDMA subcarriers of the plurality of OFDMA subcarriers; and transmit, to the subscriber unit, a second allocation of OFDMA subcarriers of the plurality of OFDMA subcarriers selected by the base station for use by the subscriber unit, after, and based on at least the receipt of the second feedback of channel and interference information. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for a wireless system employing orthogonal frequency division multiple access (OFDMA) at least on a downlink, the method comprising:
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providing, at a first step by a base station, a first pilot symbol using a plurality of OFDMA subcarriers to a subscriber unit; receiving, at a second step by the base station from the subscriber unit, first feedback information as to a plurality of dusters, each of which includes at least two OFDMA subcarriers of the plurality of OFDMA subcarriers; providing, at a third step by the base station, first allocation information as to a first plurality of OFDMA subcarriers to the subscriber unit for use by the subscriber unit; providing, at a fourth step by the base station, a second pilot symbol using a plurality of OFDMA subcarriers to the subscriber unit; receiving, at a fifth step by the base station, from the subscriber unit, second feedback information as to the plurality of clusters; providing, at a sixth step by the base station, second allocation information as to a second plurality of OFDMA subcarriers to the subscriber unit for use by the subscriber unit; the first feedback information including indices relating to a first modulation and coding rate respectively for each cluster of the plurality of clusters; and the second feedback information including indices relating to a second modulation and coding rate respectively for each duster of the plurality of dusters. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A base station for a wireless system employing orthogonal frequency division multiple access (OFDMA) at least on a downlink, the base station comprising:
a processor configured to; provide a first pilot symbol using a plurality of OFDMA subcarriers to a subscriber unit, at a first step; receive, from the subscriber unit, first feedback information as to a plurality of dusters, each of which includes at least two OFDMA subcarriers of the plurality of OFDMA subcarriers, at a second step; provide first allocation information as to a first plurality of OFDMA subcarriers to the subscriber unit for use by the subscriber unit, at a third step; provide a second pilot symbol using a plurality of OFDMA subcarriers to the subscriber unit, at a fourth step; receive, from the subscriber unit, second feedback information as to the plurality of dusters, at a fifth step; provide second allocation information as to a second plurality of OFDMA subcarriers to the subscriber unit for use by the subscriber unit, at a sixth step; the first feedback information including indices relating to a first modulation and coding rate respectively for each duster of the plurality of dusters; and the second feedback information including indices relating to a second modulation and coding rate respectively for each cluster of the plurality of clusters. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
Specification